Change visibility Parameter of a Dynamic Block in AutoCAD using .net

[CommandMethod("VDBlkAttr")]

public static void VisibilityDynamicBlockAttribute()
{
    Document doc = null;
    Database db = null;
    Editor ed = null;

    string blkName = "Block1";
    string visPropName = "VISIBILITY";
    string visPropValue = "VisVal1";

    try
    {
        doc = AcadApp.DocumentManager.MdiActiveDocument;
        if (doc == null)
            throw new System.Exception("No MdiActiveDocument");
        db = doc.Database;
        ed = doc.Editor;


        using (Transaction tr = db.TransactionManager.StartTransaction())
        {
            var bt = (BlockTable)tr.GetObject(db.BlockTableId, OpenMode.ForRead);
            if (!bt.Has(blkName))
                throw new System.Exception("Block not found: " + blkName);
            var blkId = bt[blkName];

            var ms = (BlockTableRecord)tr.GetObject(SymbolUtilityServices.GetBlockModelSpaceId(db), OpenMode.ForWrite);

            var insPnt = new Point3d(10, 20, 0);
            var blkRef = new BlockReference(insPnt, blkId);
            ms.AppendEntity(blkRef);
            tr.AddNewlyCreatedDBObject(blkRef, true);

            //Add Attributes to BlockReference, this is a separate action in C#

            BlockTableRecord blk = (BlockTableRecord)tr.GetObject(blkRef.BlockTableRecord, OpenMode.ForRead);
            // if (blkRef.IsDynamicBlock)
            //     blk = (BlockTableRecord)tr.GetObject(blkRef.BlockTableRecord, OpenMode.ForRead);
            //else
            //     blk = (BlockTableRecord)tr.GetObject(blkRef.DynamicBlockTableRecord, OpenMode.ForRead);

            foreach (ObjectId id in blk)
            {
                DBObject dbObj = (DBObject)tr.GetObject(id, OpenMode.ForRead);
                AttributeDefinition attDef = dbObj as AttributeDefinition;
                if ((attDef != null) && (!attDef.Constant))
                {
                    using (AttributeReference attRef = new AttributeReference())
                    {
                        attRef.SetAttributeFromBlock(attDef, blkRef.BlockTransform);
                        attRef.TextString = "";
                        blkRef.AttributeCollection.AppendAttribute(attRef);
                        tr.AddNewlyCreatedDBObject(attRef, true);
                    }
                }
            }
            if (blkRef.IsDynamicBlock) //comment this when it's not a Dynamic block
            {
                var dynProps = blkRef.DynamicBlockReferencePropertyCollection;
                foreach (DynamicBlockReferenceProperty dynProp in dynProps)
                {
                    if (!dynProp.ReadOnly && Regex.IsMatch(dynProp.PropertyName, visPropName, RegexOptions.IgnoreCase))
                    {
                        var allVals=dynProp.GetAllowedValues();
                        var dynVals=new Dictionary<string,string>(StringComparer.OrdinalIgnoreCase);
                        allVals.Cast<string>().ToList().ForEach(n=> dynVals[n]=n);

                        if (!dynVals.ContainsKey(visPropValue))
                            ed.WriteMessage("\n Warning: {0} Key not found: {1}. Apply Default.", visPropName, visPropValue);
                        else
                            dynProp.Value = dynVals[visPropValue];
                    }
                }
            }
            tr.Commit();
        }

    }
    catch (System.Exception ex)
    {
        if (ed != null)
            ed.WriteMessage("\n Error in VisibilityDynamicBlockAttribute: {0}", ex.Message);
    }
}

Hope you found useful information here. 

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